Assessing the surface modification of NPN chip using XPS

Since my last update I have been trying to achieve reliable size-separation of DNA by length using dwell time with the NPN pre-filter. Originally I had hoped to achieve 250-bp resolution near the optimal length for the NPN filter devices that we are working with, but that turned out to be a bit overly ambitious,…

Surface functionalization results

Roundness vs. Equivalent Diameter plots for five eccentric wafers: There really doesn’t seem to be a correlation between equivalent diameter and roundness. However, there does appear to be a rough downward trend in SC 016 and SC 258. Mean Roundness vs. Wafer Number graph with error bars included: Without the error bars, it looked like…

Since the new year there have been difficulties with charging the glass plate and the charge not being enough to capture the membrane.  Synthetic silk was tested to see if the glass charged better but no difference was seen between the silk and a crew wipe.  When materials were first being tested to use during…

This is a retrial of the negative adsorption assay using the Tecan spec/fluorimeter that we have been demo-ing. To perform this assay, I am applying a known concentration to the surface I want to test. After an hour I remove some of the solution and measuring the remaining concentration using absorption and the Bradford assay….

In order to further test the model, I’ve set up additional rhodamine diffusion assays.  In each case, the setup is similar to the nanoparticle/protein/dna separations –  20 uL of .5 mM rhodamine on the top of a SepCon and 20 uL .1 M KCl on the bottom.  Two different membrane geometries were used so far…